Project Abstract:

An increasingly useful way to study movement of marine species is with the implementation of acoustic telemetry, which bypasses the coarseness of older techniques such as mark and recapture. However, the ability to quantify this type of data in an ecologically meaningful way is still in its infancy. A progressively common modeling tool to visually analyze broad-scale telemetry data is using network analyses, which can elucidate movement behavior, habitat preference, and connectivity between individuals and the environment. In addition, the integration of positioning systems can generate an even finer understanding of daily movements and habitat partitioning within and between species. For this study, a total of 15 yellowtail snapper Ocyurus chrysurus were tagged with acoustic transmitters in Buck Island Reef National Monument (BIRNM), a marine protected area in the U.S. Virgin Islands, managed by the National Park Service. The array consisted of 111 passive acoustic receivers, with 28 of those nested in a VEMCO Positioning System (VPS). Individual fish were continuously tracked for an approximate eighteenth month period, from May 2015 to November 2016. Network analyses, for the 9 individuals with the most robust detection history, indicated a strong association of all fish to a particular area of the array. A binomial generalized linear mixed model, with individual fish as a random effect, showed that yellowtail snapper preferred the habitat and bottom depth associated with the region where the VPS was placed, which is well within the boundaries of the monument. Fine-scale movement analyses showed distinct space use patterns between fish, reduced movement at night, and potential habitat selectivity. The results suggest that BIRNM may be providing adequate spatial protection for the individuals tracked and will allow these analytical tools to be directly applied to understanding the spatial dynamics of several other important species inhabiting BIRNM.

Future work among the many collaborators and institutions tagging a wide variety of animals (from conch, turtles, sharks, and fish!) within BIRNM will focus on developing an overarching ecosystem perspective of how species interact with one another, the extent of habitat partitioning, and general and specific space use patterns in one of the oldest Caribbean MPAs.